JPH0463338B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION BACKGROUND OF THE INVENTION The present invention relates to gas analyzers and, more particularly, to non-dispersive optical gas analyzers that use multiple thermopiles as optical energy detectors.

Various types of non-dispersive infrared gas analyzers have been developed over the years to measure gas concentrations in applications such as medicine, pollution monitoring, and industrial process control. Examples of such gas analyzers include U.S. Pat.
No. 4,069,420 granted to Ross, December 1983
No. 4,420,687, granted to MS Martinez et al., May 13, and assigned to the assignee of the present invention.

A common feature of conventional gas analyzers of the type described above is the use of a single infrared detector that detects infrared radiation in the form of a pulse train of light energy. These pulses alternately indicate the amount of infrared energy absorbed by a particular gas in the sample gas mixture and the amount of infrared energy absorbed by the reference gas. Appropriate electronic circuitry processes the detector signal (also in the form of a pulse train) and generates a signal proportional to the concentration of this particular gas in the sample.

Alternating pulses of light energy are typically provided by a perforated motor-driven chopper wheel. This wheel rotation in conjunction with the hole position relative to the radiation source produces the desired alternating pulses.

The main reason for using alternating pulse operation is that a single detector is required to measure both the sample and reference gases. Previous designs were limited to the use of a single infrared detector because it was not possible to create an analyzer with the required precision by preparing multiple detectors with sufficiently precisely matched performance. It comes from this.

For example, infrared sensors are very sensitive to small changes in ambient temperature, and the responsiveness of two separate detectors to such small changes is not necessarily the same. Therefore, it is an object of the present invention to provide a multi-detector gas analyzer capable of obtaining accurate measurements under varying ambient temperature conditions without relying on expensive, complex and often unreliable temperature compensation devices and circuits. was considered extremely difficult.

Conventional gas analyzer with motor-driven chopper
The need for wheels inevitably increases the size of the device, requires significantly more power, and results in an inability to withstand high levels of shock and vibration.

Accordingly, it is an object of the present invention to provide a new and improved non-dispersive optical gas analyzer.

Another object of the invention is that it may be compact and low power;
An object of the present invention is to provide a non-dispersive optical gas analyzer that does not require a motor-driven chopper wheel.

Another object of the present invention is to provide a portable, low cost, highly accurate, non-dispersive optical gas analyzer that uses multiple optical detectors and can operate over a wide spectrum of wavelengths from infrared to ultraviolet. It is about providing.

SUMMARY OF THE INVENTION The foregoing and other objects of the present invention include a radiation source that produces a directional beam of optical energy and a generally cylindrical cylinder containing a sample gas for analyzing one or more components to determine their concentration in a mixture. This is accomplished by a non-dispersive optical gas analyzer that includes a shaped cell. When sampling one gas component in a mixture, two optical detectors are used, one serving as a reference detector and the other serving as a sample detector;
Optical energy passing through the sample gas cell is detected.

Each detector is in the form of a thermopile consisting of a number of thermocouple connections, each thermocouple connection generating a thermal emf proportional to its temperature. A thermopile consists of a row of thin films of dissimilar metals deposited on a thermally conductive substrate. A portion of each thermopile is shielded from light energy leaving the cell. The shielded portion of each thermopile is used to correct the thermocouple output signal for changes in ambient temperature.

A first filter is placed between the cell and the unshielded portion of the sample thermopile;
The wavelength of the light energy incident on that portion of the thermopile is limited to the range in which the light energy is absorbed by one gas component within the sample mixture.

A second filter is placed between the cell and the unshielded portion of the reference thermopile to limit the wavelength of light energy incident on that portion of the thermopile to the reference wavelength range.

A control circuit is used that subtracts a reference thermopile signal from the sample thermopile signal and divides the subtracted value by the reference thermopile signal.

Other objects, features and advantages of the invention will become apparent from the following description taken in conjunction with the drawings. Note that in the drawings, similar components are designated by similar reference numerals.

FIG. 1 is a perspective view of a gas analyzer 10 constructed in accordance with the present invention. The analyzer 10 consists of generally cylindrical sections 12, 14, 16, 18 which are held tightly together by bolts extending therethrough.

Figure 2 shows the analyzer 1 along line 2-2 in Figure 1.
FIG. Section 12 is preferably made of aluminum or the like and is used to support a radiation source 24 in the form of a platinum wire bead or the like. A cable 26 connects wire bead 24 to an external power source, such as a battery. When connecting,
The wire bead provides a source of light energy. The portion of section 12 surrounding bead 24 is in the form of a parabolic reflector to direct light energy to an adjacent end of section 14.

Section 14 (preferably made of plastic or the like) contains a generally cylindrical cell 28 containing the sample gas mixture to be analyzed. The inlet and outlet ends of the cell 28 are provided with windows 30, 32 which are held in place by O-rings to form an airtight container.
The window may be made of a material, such as sapphire, that is substantially transparent to light energy from source 24 over the wavelength range used to analyze the gas mixture. The cell 28 has an inlet 36 and an outlet 3
8 is provided to allow sample gas to enter and exit the cell 28.

A section 16 (preferably made of a thermally conductive material such as aluminum, brass, stainless steel, etc.) is mounted adjacent the outlet end of the cell 28. Section 16 is used to mount an optical detector assembly 40 that is used to measure the light energy exiting cell 28.

Optical detector assembly 40 is housed within a generally cylindrical metal can 42 similar to those used to house transistors. One type of such container is known to those skilled in the art as a TO-8 housing. Housing 42 includes a transparent window 44, such as sapphire. Within housing 42 is a flat base 46 approximately ten millimeters in diameter and constructed of a thermally conductive insulating material such as beryllium or aluminum oxide. Mounted on one side of the substrate 46 is a row 48 of four thermopiles formed by interconnected lines of dissimilar metal thin films deposited on the surface of the substrate. This type of thermopile is located in Dexter, Michigan.
Manufactured by Dexter Research Center, Inc.

Four filters 50, 52, 54, 5 are provided on the opposite surface of the base 46 (the surface facing the window 32 of the cell 28).
6 are provided such that only selected wavelengths of the light energy leaving the cell 28 are filtered through the thermally conductive substrate 4.
6 and into a predetermined area of the thermopile 48. The remainder of this side of the substrate is covered with an optical masking material 58, such as aluminum, to effectively prevent light energy exiting the cell 28 from passing through the substrate 46 to the area provided with the material 58. .

Substrate 46 is partially embedded within header 62 and is supported by conductive leads 60 extending therethrough. A header 62 made of epoxy or other suitable material serves to close off the bottom of the housing 42 to create an airtight assembly 40. The space between substrate 46 and header 62 may be filled with a thermally conductive material, such as epoxy, to increase thermal conductivity between these two components. lead 6
0 provides an electrical connection to thermopile 48. The metal housing 42 is rigidly attached to a thermally conductive section 16 that has a significantly greater thermal mass than the housing 42 and acts as a large area heat sink to respond to rapid changes in analyzer ambient temperature. is adapted to reduce the rate of temperature change of the assembly 40.

Leads 60 pass through openings in assembly 16 and connect to conductive pads in section 18 (in the form of a printed wiring board). Printed wiring board 18 includes electronic elements 64 that process the voltage generated at thermopile 48 to generate a signal indicative of the concentration of one or more gas components within the sample gas mixture. Occur. cable 6
6 provides power to the circuit and is adapted to send circuit output signals to a suitable display device.

FIG. 3 is a side view of the base 46 showing the structure of the thermopile 48 in detail. Thermopile 48 consists of four thermopiles 68, 70, 72, and 74. Each thermopile consists of a plurality of thermocouple connections, and each thermocouple connection generates a thermal EMF proportional to its temperature. Each thermocouple connection is formed by interconnecting thin wires of different metals. These metal lines are attached to the surface of the substrate using thin film deposition techniques well known to those skilled in the art. One advantage of using thermocouples as optical energy detectors is that they respond to stable levels of radiation over a wide wavelength range from infrared to ultraviolet. Thermopile 68 will be described in detail below to explain the structure of each thermopile.

As shown in FIGS. 3 to 3A, the thermopile 68
contains a number of metal wires which are joined at their ends to adjacent wires like a wreath of daisies (e.g. with pads of precious metal such as gold), A long series circuit having terminals 76 and 78 is formed. The metals in adjacent lines are in most cases different from each other. For example, bismuth metal wires are alternated with antimony metal wires. When these wires are joined at the ends, a thermocouple connection is formed.
Referring to the polarity of the thermal EMF generated by each thermocouple,
Terminal 76 can be said to be a positive terminal with respect to terminal 78. The polarity defined at each connection is determined by the arrangement of the two metal wires that make up the connection. Therefore, the particular polarity is determined by the type of metal deposited on each of the thermopile wires.

The arrangement of the metal wires of thermopile array 68 is selected to provide thermocouple connections having polarities indicated by the + or - symbols shown adjacent each connection in FIG.
As can be seen, the connections are arranged in four columns and multiple rows. Starting from the leftmost column 80 , a first group 82 of four positive polarity thermocouple connections is provided which alternates in series with a first group 84 of three negative polarity connections in column 86 . are interconnected to form a first series circuit. This first series circuit is connected between terminal 76 and conductive pad 88, which may be formed of gold, silver, or the like. Column 86 is column 80
by the side and separated from it by about 0.6 mm.

A group 90 of eight negative polarity connections following group 82 of column 80 is connected in series with seven positive polarity connections following group 84 of column 86 to form a second series circuit; A series circuit is connected between pad 88 and pad 94 of similar construction. Group 96 of four positive connections following group 90 of column 80 is group 9 of column 86
2 followed by a group 98 of three negative polarity connections to form a third series circuit, which is connected between pad 94 and the last metallized row of column 80.

A group 100 of three negative polarity thermocouple connections is provided in a column 102 that is adjacent to column 86 . Connections in group 100 are connected in series with group 104 of four positive polarity connections in column 106 about 0.6 millimeters apart apart from column 102 and are connected in series with terminal 78 and pad 108 similar to pad 88. A fourth series circuit is formed between the two.

A group 110 of seven positive polarity connections following group 110 of row 102 is connected in series with group 112 following group 104 of column 106 and connects between pad 108 and pad 114 similar to pad 88. Form a series circuit of 5. A group 116 of three negative polarity connections following group 110 of column 102 is connected in series with a group 118 of four positive polarity connections following group 112 of column 106 to form a sixth series circuit; It connects between the pad 114 and the bottom metallization row extending from the connection of the third series circuit group 96.

As can be seen from the above description, the first through sixth series circuits of thermopile 68 are sequentially connected in series to form one long thermopile circuit between terminals 76 and 78. The structure of thermopiles 70, 72, 74 is similar to the structure of thermopile 68. Thus, the thermopile 70 is organized into four columns, with terminals 120,
It is in the form of a series interconnection of thermocouple connections terminating at 122. Similarly, the series circuit consisting of thermopile 72 terminates at terminals 124, 126, and the series circuit consisting of thermopile 74 terminates at terminals 124, 126.
It ended at 8,130. The polarity symbols in FIG. 3 are similar to those for thermopile 68 and
Various thermocouple connection polarities of 0, 72, and 74 are shown.

The active portions of each thermopile 68, 70, 72, 74 responsive to the light energy to be measured are indicated by dashed lines 132, 134, 136, 1, respectively, in FIG.
38. As can be seen, this active area is limited to the positive thermocouple connections in the central two columns of each thermopile. Therefore, for thermopile 68, the active area is junction group 9
Limited to 2,110.

The thermocouple active area is defined using the masking material 58 previously described. This masking material is provided as a coating on the side of the substrate 46 opposite the thermopile side. This coating covers the thermopile 4 of the substrate except for the area immediately following the dashed line areas 132-138.
Covers almost all of the back sides of 8. Masking material 58 allows light energy emanating from cells 28 to pass through the portion of thermally conductive substrate 46 covered with the masking material and into the portion of row 48 located immediately after masking material 58 on the opposite side of substrate 46. prevent.

Using thermopile 68 as an example (see FIG. 3A), thermocouple connections 82, 86, 90, 96, 9
8, 100, 104, 112, 116, 118 are shielded with masking material and cell 28
Only groups 92, 110 remain that can detect light energy passing through the substrate 46 from the substrate 46. The ten groups of connections, shielded with masking material, are used to temperature correct the signal produced by the thermopile 68 for temperature changes in the substrate 46, such as those caused by changes in the ambient temperature of the analyzer 10.

Thermopiles 68-74 are sample gas cells 28
It is important that the voltage signal is not significantly affected by changes in ambient temperature, as it is used to provide a voltage signal that is a measurement of the amount of light energy of a given wavelength emitted by the device. If influenced, measurement errors will occur. It has been found that changes in ambient temperature create a non-linear temperature gradient across the surface of the substrate 46. Such temperature gradients can cause significant errors in the voltage produced by the active thermocouple group. Therefore, ideally it should respond only to the light energy emanating from cell 28.

Additionally, by surrounding the active thermocouple connection group of each thermopile with a temperature compensation group in the arrangement shown in Figure 3, nonlinear temperature effects caused by changes in ambient temperature can be compensated for by the voltage generated by these compensation groups. I also found out that it can be corrected.

Additionally, the actual number of thermocouple connections in each of the 12 groups of a thermopile may be determined as a result of empirical or experimental analysis of the nonlinear temperature gradient across the substrate 46 to more accurately determine temperature changes. Can be corrected. Therefore, the number of connections in a particular group will vary from thermopile to thermopile depending on the location of the thermopile on the substrate 46. Thus, the third
Although each of the illustrated thermopiles 68-74 is shown as having the same number of connections in the corresponding group, the invention is in no way limited to this configuration.

Each of thermopiles 68-74 is used to sense light energy over a particular wavelength range as it exits cell 28. This particular wavelength range that each thermopile is intended to detect is based on the particular gas component within the mixture that is intended to be analyzed. One of the four thermocouples, e.g., thermocouple 70, is made to respond to a range of wavelengths where the light energy does not coincide with the wavelength at which it is absorbed by any of the gaseous components to be analyzed in the mixture. There is. As explained below, this particular thermopile 70 will be referred to as the reference thermopile.

The remaining three thermopiles 68, 72, and 74, referred to as sample thermopiles, are each used to detect radiation at a wavelength at which a particular gas component is absorbed within the mixture. These three thermopiles can therefore provide signals for the analysis of three gas components. Obviously, if only one gaseous component in a mixture is desired to be analyzed, just one sample thermocouple in addition to the reference thermopile is all that is needed.

The wavelength of the light energy reaching each thermopile is limited to the desired range by mounting the four optical bandpass filters 50-56 previously described on the opposite side of the substrate 46 from which the array 48 is mounted. Each filter 50, 52, 54, 56 corresponds to the area 1 shown in broken line in FIG.
32, 134, 136, and 138.

For example, if the analyzer 10 is to be used to analyze three components of automobile exhaust gas, such as CO ₂ , CO, and NO, using the thermopiles 68, 72, and 74, respectively, the filter 50 covering the area 132 is The filter 54 covering region 136 will have a center wavelength of about 4.27 microns and a bandwidth of about 110 nanometers corresponding to the amount of CO ₂ absorption.
The region 138 is chosen to have a bandwidth of approximately 100 nanometers corresponding to the amount of CO absorption
The filter 56 will be chosen to have a center wavelength of 2.85 microns and a bandwidth of about 170 nanometers corresponding to the amount of NO absorption. The filter 52 covering the region 132 of the reference thermopile 68 has a center wavelength of 4.0 microns and a wavelength range corresponding to approximately 4.0 microns that does not intersect the absorption spectra of any of the other components of interest in the mixture.
and a bandwidth of 240 nanometers.

Filters 50 to 56 each have an active region 13.
It is only necessary to cover 2 to 138, but
These filters, made of thin plates of materials such as germanium or potassium bromide, are usually made larger than the active area. The increased size makes it easier to fabricate filters that are typically cut from larger sheets. The large size also allows the edges of the filter, which can be slightly abraded during cutting operations, to be located outside the active area.

The operation of the analyzer 10 described so far is as follows. Referring to FIG.
4, light energy is directed by reflector 12 through a cell 28 that has been previously filled with a sample gas mixture. Light energy exiting cell 28 through window 32 is directed to substrate 46, which includes masking layer 58 and filters 50-56.
incident on the side of

Masking layer 58 directs light energy to active region 132 of thermopile 48 located on the opposite side of substrate 46.
Prevent it from reaching anywhere other than ~138. On the other hand, filters 50-56 transmit only selected wavelengths of optical energy to respective active regions 132-138.
Pass it through.

Each of the thermopiles 68-74 generates a voltage related to the amount of light energy sensed by its respective active region, and the other regions of each thermopile generate a thermopile voltage for changes in ambient temperature. Correct. Temperature-compensated thermopile voltage (terminal pair 76-78,
120-122, 124-126, 128-13
0) is provided as an input signal to a control circuit which operates as follows.

With reference to FIG. 4, thermopiles 68, 72, 74
signals from detector assembly 40 through leads 60 to differential amplifiers 140, 142, and 14, respectively.
It is given to the positive input terminal of 4. It is assumed that these amplifiers provide adjustable offset and gain factors for each input signal. These amplifiers are mounted on printed wiring board 18, draw their power through cable 66, and measure their signals with respect to the illustrated ground terminal. The signal from reference thermopile 70 is routed through scaling amplifier 145 to all three amplifiers 14.
It is applied to the negative input terminals of 0, 142, and 144, and also to the divisor input terminals of three division elements 146, 148, and 150. These division elements 14
6-150 also draws power through cable 66 and is mounted on printed wiring board 18 to measure the signal with respect to the illustrated ground terminal.

The output terminals of amplifiers 140, 142, 144 are
They are sent to the divisible number input terminals of division elements 146, 148, and 150, respectively. As is clear from the above description of the circuit shown in FIG.
Each of the signals from 8, 72, 74 has the signal from the reference thermopile 70 subtracted therefrom. Each subtraction result is sequentially divided by the signal from the reference thermopile 70. Each division result is sent to a division circuit 146,
148, 150 output terminals 152, 154, 15
6 as an output signal. As shown, the signals appearing at these output terminals are directly related to the concentration of gas components corresponding to the absorption spectra of the respective filters 50, 54, 56 described above.

The signals on lines 152, 154, and 156 may be provided to a display and recording device after appropriate filtering and linearization operations in a manner well known to those skilled in the art.
Many other circuits may be used to perform the functions described above. For example, microprocessor elements may be used to perform computational functions.

Although the invention has been disclosed and described in detail with respect to certain specific embodiments, it is not intended to limit the invention to only those embodiments. Many modifications may be made by those skilled in the art within the spirit and scope of the invention. Accordingly, the invention is limited only by the scope of the claims appended hereto.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a gas analyzer constructed in accordance with the teachings of the present invention. Figure 2 is 2 of Figure 1.
2 is a cross-sectional view along line -2 showing the internal arrangement of the components of the analytical device of FIG. 1; FIG. 3 is a side view of a thermally conductive substrate supporting a plurality of thermopiles used as optical energy detectors in the gas analyzer of FIG. 1; FIG. FIG. 3A is an enlarged fragmentary detail of the upper right quadrant of the substrate of FIG. 3; FIG. 4 is a schematic block diagram of a control circuit used to process the voltage generated in the thermopile to provide an indication of gas concentration. Explanation of symbols of main parts, 10...Gas analyzer, 12, 14, 16, 18...Cylindrical section, 24...Radiation source, 26...Cable, 28
... Cell, 30, 32 ... Window, 36 ... Entrance, 3
8...Exit, 40...Photodetector assembly, 42...
Metal can, 44...Transparent window, 46...Base, 48
...Thermopile rows, 50, 52, 54, 56...
Filter, 58... Masking material, 60... Lead, 62... Header, 64... Electronic element, 66
...Cable, 68,70,72,74...Thermopile, 76,78...Terminal, 132,134,1
36,138...active region, 140,142,1
44... Differential amplifier, 146, 148, 150...
...Division element.

Claims (1)

[Scope of Claims] 1. A radiation generating means for generating a directional beam of light energy, and a gaseous mixture adapted to analyze at least one component to determine its concentration; a generally cylindrical cell having first and second ends that are transparent to each other, and a number of thermocouple connections, each of which generates a thermal emf proportional to its temperature. a first thermopile arranged in a plurality of rows in a first column;
a plurality of second thermocouple connections arranged in a plurality of rows in a second column adjacent to the first column; and a third column adjacent to the second column. a plurality of third thermocouple connections arranged in a plurality of rows in a plurality of rows; a plurality of fourth thermocouple connections arranged in a plurality of rows in a fourth column adjacent to the third column; A first group of thermocouple connections in the A row of the column is connected in series with a first group of thermocouple connections in the B row of the second column to form a first series circuit; Heat generated at each row connection
a first connection means for the EMF to be of a common polarity that is opposite to the polarity of the thermal emf generated in each of the connections of the first B row, and following the thermocouple connections of the A row of the first column; A second group of C rows is connected in series with a second group of D rows following the B row of thermocouple connections in the second column to form a second series circuit, so that a a second connection means for making the thermal emfs generated at each of the connections in the A and D rows of a common polarity opposite to the polarity of the thermal EMFs generated at each of the connections in the A and D rows; A third group of subsequent E rows is connected in series with a third group of F rows that follows the D row of the second column connections to form a third series circuit, so that a third group of E rows occurs at each of the E row connections. third connection means for the thermal emf to be of a common polarity that is opposite to the polarity of the thermal emf generated at each of the connections in the C and F rows; connecting one group in series with the first group of H rows of thermocouple connections in a fourth column to form a fourth series circuit;
The thermal emf generated at each connection in the G row is the first
Thermal EMF generated at each of the connections in rows A and H of
a second group of I rows following the G row of the thermocouple connections of the third column to the H row of the connections of the fourth column; A fifth series circuit is formed by connecting the second group of J rows in series, so that the thermal EMF generated at each connection in the I row is equal to the thermal EMF generated at each connection in the C and J rows. a fifth connection means of a common polarity opposite to the polarity, and a third group of K rows following the I row of the third column of thermocouple connections following the J row of the fourth column of connections; Connect in series with the third group of L rows to form a sixth series circuit, so that the thermal emf generated at each of the connections of the K row has the polarity of the thermal EMF generated at each of the connections of the E and L rows. and a sixth connecting means of a common polarity opposite to that of A, D, and the first to sixth series circuits are connected together in series to form a first thermopile series series circuit;
seventh connection means for connecting the connections of the E, H, I, and L rows in a series-assisted configuration; and a plurality of thermocouple connections; Each of the pair connections has a second thermopile generating a thermal emf proportional to its temperature, the thermopile having a plurality of fifths arranged in a plurality of rows in a fifth column.
a plurality of sixth thermocouple connections arranged in a plurality of rows in a sixth column located next to the fifth column; and a plurality of sixth thermocouple connections arranged in a plurality of rows in a sixth column located next to the sixth column. a plurality of seventh thermocouple connections arranged in a plurality of rows; a plurality of eighth thermocouple connections arranged in a plurality of rows in an eighth column adjacent to the seventh column; and a fifth column. a first group of M rows of thermocouple connections in a sixth column are connected in series with a first group of N rows of thermocouple connections in a sixth column to form a seventh series circuit; The heat generated at each of the connections
an eighth connecting means for the EMF to be of a common polarity that is opposite to the polarity of the thermal emf generated in each of the first N rows of connections; and following the M rows of thermocouple connections of the fifth column. The second group of O rows is connected in series with the second group of P rows following the N rows of connections in the sixth column to form an eighth series circuit, and the heat generated at each of the connections in the O rows is a ninth connection means for the EMF to be of a common polarity which is opposite to the polarity of the thermal emf generated at each of the connections in the M and P rows; and Q following the O row of thermocouple connections in the fifth column. The third group of rows is connected in series with the third group of R rows following the P rows of the connections of the sixth column to form a ninth series circuit, and the thermal emf generated at each of the connections of the Q rows is a tenth connection means having a common polarity which is opposite to the polarity of the thermal EMF generated at each of the connections in the O and R rows; and a first connection means for the thermocouple connections in the S row of the seventh column. group in series with the first group of thermocouple connections in the T row of the eighth column to form a tenth series circuit such that the thermal emf generated at each of the connections in the S row is connected in series with the first group of thermocouple connections in the T row of the eighth column. an eleventh connection means of a common polarity opposite to the polarity of the thermal EMF generated at each of the connections; and a second group of U rows following the S row of thermocouple connections of the seventh column. The connections in the 8th column are connected in series with the second group of V rows following the T row to form an 11th series circuit, so that the thermal EMF generated at each of the connections in the U row is transferred to the O and V rows. a twelfth connection means having a common polarity opposite to the polarity of the thermal EMF generated in each of the connections; and a third group of W rows following the U row of thermocouple connections of the seventh column. The 8 column connections are connected in series with the third group of a thirteenth connecting means of a common polarity that is opposite to the polarity of the thermal EMF generated in each of the sections; Form a series circuit, M, P,
a fourteenth connecting means for connecting the Q, T, U, and X rows in a series-assisted configuration; a thermopile mounting means disposed on the substrate, the radiation generating means, the cell and the thermopile substrate being positioned such that a beam of light energy is directed axially through the cell toward the first and second thermopile. A, B, C, E, F, G, H of the first thermopile,
The thermocouple connections in the J, K, L rows and the M, N, O, Q, R, S, T, V, W, X thermocouple connections in the second thermopile row are connected to the light energy emitted from the cell. masking means for shielding from the beam of the first thermopile; and a masking means installed between the cell and the thermocouple connections of the D and I rows of the first thermopile column, the masking means for shielding from the beam of the first thermopile; a first filter means for restricting light energy to the extent that it is absorbed by said gaseous components in the gas mixture; and a first filter means disposed between the cell and the thermocouple connections of the P, U rows of the second thermopile. a second filter means for limiting the wavelength of optical energy incident on the connections in the P, U rows to a reference wavelength range; Measure an EMF representative of a first signal related to the amount of light energy incident thereon, and measure an EMF representative of a first signal related to the amount of light energy incident thereon, and measure an EMF representing a first signal related to the amount of light energy incident on the second thermopile series circuit and incident on the connection of the P, U rows. and control means for measuring an EMF representing the second signal, subtracting the first signal from the second signal to generate a third signal, and dividing the third signal by the second signal. Gas analyzer. 2. In the gas analyzer according to claim 1, numerical values A, H, E, and L are equal to each other, numerical values C and J are equal to each other, numerical values D and I are equal to each other, and numerical values B, G, F, A gas analyzer characterized in that K are equal to each other. 3. In the gas analyzer according to claim 1, the numerical values M, T, Q, and X are equal to each other, the numerical values O and V are equal to each other, the numerical values P and U are equal to each other, and the numerical values N, S, R, A gas analyzer characterized in that W is equal to each other. 4. The gas analyzer according to claim 1, wherein the thermocouple connection portion is formed by depositing thin films of different metals on a base and interconnecting them.